National Advisory Committee for Aeronautics (NACA) - 27 Matching Results

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Aerodynamic and hydrodynamic tests of a family of models of flying-boat hulls derived from a streamline body: NACA model 84 series

Description: Report presenting a series of related flying-boat hull forms with various combinations of aerodynamic and hydrodynamic requirements that were tested in an NACA tank and high-speed tunnel. Effects explored included varying the height of the bow, varying the height of the stern, increasing the angle of dead rise at the bow, decreasing the angle of dead rise on the afterbody, increasing the depth of step, increasing the angle of afterbody keel, adding chine flare, adding a third planing surface, and rounded chines at the bow.
Date: September 1943
Creator: Parkinson, John B.; Olson, Roland E.; Draley, Eugene C. & Luoma, Arvo A.
Partner: UNT Libraries Government Documents Department

An approximate method of shear-lag analysis for beams loaded at right angles to the plane of symmetry of the cross section

Description: Report discussing strain measurements made on a box beam of triangular cross section and on two beams of D-section under transverse bending. Information about the arrangement of the beams and experimental and calculated stresses for different boxes.
Date: September 1943
Creator: Kuhn, Paul & Brilmyer, Harold G.
Partner: UNT Libraries Government Documents Department

Calculated and measured turning performance of a Navy F2A-3 airplane as affected by the use of flaps

Description: Report presenting results of flight tests to determine the turning performance of a Navy F2A-3 airplane over a range of speeds for three flap deflections at two altitudes. The results are correlated with an analytical study of turning performance in which the effect of thrust on maximum lift coefficient was considered.
Date: September 1943
Creator: Clousing, Lawrence A.; Gadeberg, Burnett L. & Kauffman, William M.
Partner: UNT Libraries Government Documents Department

Critical compressive stress for curved sheet supported along all edges and elastically restrained against rotation along the unloaded edges

Description: From Summary: "A formula is given for the critical compressive stress for slightly curved sheet with equal elastic restraints against rotation along the unloaded edges. The theory of small deflections is used and the formula reduces to that given by Timoshenko for the case of simply-supported edges. For larger curvatures, a modification of Redshaw's formula to include the effect of edge restraint is suggested."
Date: September 1943
Creator: Stowell, Elbridge Z.
Partner: UNT Libraries Government Documents Department

The effect of xylidines on the load-carrying capacity of an aircraft engine oil II

Description: Report presenting testing of the effect of xylidines on the load-carrying capacity of an aircraft-engine oil in several test devices. There is also interest in the suitability of xylidines as an antiknock component in aviation gasoline, so xylidines were added to the gasoline mixes used in several different machines.
Date: September 1943
Creator: Olson, Walter T. & Spurr, Robert A.
Partner: UNT Libraries Government Documents Department

General porpoising tests on flying-boat-hull models

Description: Report presenting evidence in support of the propriety of substituting a general porpoising test of flying boat hull models in place of the usual specific test. The results of a general test are presented and compared with the results of a specific test of the same model.
Date: September 1943
Creator: Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Heat Transfer Through Turbulent Friction Layers

Description: The "general Prandtl number" Pr(exp 1) - A(sub q)/A Pr, aside from the Reynolds number determines the ratio of turbulent to molecular heat transfer, and the temperature distribution in turbulent friction layers. A(sub q) = exchange coefficient for heat; A = exchange coefficient for momentum transfer. A formula is derived from the equation defining the general Prandtl number which describes the temperature as a function of the velocity. For fully developed thermal boundary layers all questions relating to heat transfer to and from incompressible fluids can be treated in a simple manner if the ratio of the turbulent shear stress to the total stress T(sub t)/T in the layers near the wall is known, and if the A(sub q)/A can be regarded as independent of the distance from the wall. The velocity distribution across a flat smooth channel and deep into the laminar sublayer was measured for isothermal flow to establish the shear stress ratio T(sub t)/T and to extend the universal wall friction law. The values of T(sub t)/T which resulted from these measurements can be approximately represented by a linear function of the velocity in the laminar-turbulent transition zone. The effect of the temperature relationship of the material values on the flow near the wall is briefly analyzed. It was found that the velocity at the laminar boundary (in contrast to the thickness of the laminar layer) is approximately independent of the temperature distribution. The temperature gradient at the wall and the distribution of temperature and heat flow in the turbulent friction layers were calculated on the basis of the data under two equations. The derived formulas and the figures reveal the effects of the Prandtl number, the Reynolds number, the exchange quantities and the temperature relationship of the material values.
Date: September 1943
Creator: Reichardt, H.
Partner: UNT Libraries Government Documents Department

Measurements of the flying qualities of a Bell P-39D-1 airplane (AAF NO. 41-28378)

Description: Report discussing an investigation of the flight qualities of the Bell P-39D-1 airplane. Information about the longitudinal stability and control characteristics, lateral and directional stability and control, stalling characteristics, and control friction is provided.
Date: September 21, 1943
Creator: Johnson, Harold I.; Liddell, C. J. & Hoover, H. H.
Partner: UNT Libraries Government Documents Department

NACA Investigation of a Jet-Propulsion System Applicable to Flight

Description: Following a brief history of the NACA investigation of jet propulsion, a discussion is given of the general investigation and analysis leading to the construction of the jet-propulsion ground-test mock-up. The results of burning experiments and of test measurements designed to allow quantitative flight performance predictions of the system are presented and correlated with calculations. These calculations are then used to determine the performance of the system on the ground and in the air at various speeds and altitudes under various burning conditions. The application of the system to an experimental airplane is described and some performance predictions for this airplane are made.
Date: September 17, 1943
Creator: Ellis, Macon C. & Brown, Clinton E.
Partner: UNT Libraries Government Documents Department

Notes on the skipping of seaplanes

Description: Report discusses five tests related to seaplane skipping and attempts to prevent it by changing the depths of step to avoid large suction force on the afterbody generated by the flow behind a shallow step. Flying boats of various sizes and weights were tested during landing and several degrees of trim were tested for boats that had a particularly shallow step. Design suggestions for future flying boats are also included.
Date: September 1943
Creator: Parkinson, John B.
Partner: UNT Libraries Government Documents Department

Periodic Heat Transfer at Small Pressure Fluctuations

Description: The effect of cyclic gas pressure variations on the periodic heat transfer at a flat wall is theoretically analyzed and the differential equation describing the process and its solution for relatively. Small pressure fluctuations developed, thus explaining the periodic heat cycle between gas and wall surface. The processes for pure harmonic pressure and temperature oscillations, respectively, in the gas space are described by means of a constant heat transfer coefficient and the equally constant phase angle between the appearance of the maximum values of the pressure and heat flow most conveniently expressed mathematically in the form of a complex heat transfer coefficient. Any cyclic pressure oscillations, can be reduced by Fourier analysis to harmonic oscillations, which result in specific, mutual relationships of heat-transfer coefficients and phase angles for the different harmonics.
Date: September 1, 1943
Creator: Pfriem, H.
Partner: UNT Libraries Government Documents Department

Representative operating charts of propellers tested in the NACA 20-foot propeller-research tunnel

Description: Report presents the results of tests of full-scale propellers made in the 20-foot propeller-research tunnel (PRT) at the Langley Memorial Aeronautical Laboratory. The power coefficients of all dual-rotating propellers in the report represent the sum of the power coefficients of the front and rear propellers and are for the test conditions in which blade angles of the front and rear propellers were set to absorb approximately equal power at peak efficiency only.
Date: September 1943
Creator: Gray, W. H. & Mastrocola, Nicholas
Partner: UNT Libraries Government Documents Department

Requirements for auxiliary stiffeners attached to panels under combined compression and shear

Description: Panels of aluminum alloy sheets, framed by side and end stiffeners, were subjected to combined loading by means of offset knife edges applying loads to top and bottom end plates with reacting forces against the end plates supplied by laterally acting rollers. The test specimens were 17S-T aluminum alloy shoots 0.040 inch thick in panels of 10-inch width and three different lengths (approximately 10, 26, and 30 inch). Data were obtained for the bowing of transverse and longitudinal ribs of rectangular cross section and varying depths mounted on one side of the sheet only, for several ratios of compression to shear loads. Limiting values of the moments of inertia were calculated from these measurements. The experimental values exceed the theoretical values given by Timoshenko for the case of simply supported sheets with uniformly distributed boundary stresses. The work reported includes measurements of the effective shear moduli of the nine test panels with and without ribs. These data are compared with values published by Lahdo and Wagner.
Date: September 16, 1943
Creator: Scott, Merit & Weber, Robert L
Partner: UNT Libraries Government Documents Department

Some analyses of systematic experiments on the resistance and porpoising characteristics of flying-boat hulls

Description: Report discusses the results of analyses and test results of the porpoising characteristics of flying boats. Equations for calculating stability limits with given hull forms under various combinations of loading and aerodynamic conditions and for modifications of the afterbody are provided.
Date: September 1943
Creator: Davidson, Kenneth S. M. & Locke, F. W. S., Jr.
Partner: UNT Libraries Government Documents Department

Some notes on the determination of the stick-fixed neutral point from wind-tunnel data

Description: From Summary: "Two methods are presented for determining the horizontal location of the stick-fixed neutral point from wind-tunnel data. One method involves the solution of a mathematical equation; whereas the other method is a graphical solution for the same mathematical equation. The combined horizontal and vertical variation of the neutral point completely describes the stick-fixed longitudinal stability of airplanes that have large allowable center-of-gravity shifts."
Date: September 1943
Creator: Schuldenfrei, Marvin
Partner: UNT Libraries Government Documents Department

The strength of thin-wall cylinders of D cross section in combined pure bending and torsion

Description: The results of tests of 56 cylinders of D cross section conducted in the Aeronautical Laboratory of the University of Maryland are presented in this report. These cylinders were subjected to pure bending and torsional moments of varying proportions to give the strength under combined loading conditions. The average buckling stress of these cylinders has been related to that of circumscribing circular cylinders for conditions of pure torsion and pure bending and the equation of the interaction curve has been determined for conditions of combined loading.
Date: September 1, 1943
Creator: Sherwood, A W
Partner: UNT Libraries Government Documents Department

Theory of mechanical oscillations of rotors with two hinged blades

Description: Report discusses an investigation into the mechanical stability of a rotor with two vertically hinged blades mounted on symmetrical supports of equal stiffness and mass. Information about the instability regions and effect of damping is included. The two-blade rotor was found to have two shaft-critical speeds at which instability can occur as well as a second region at which self-excited vibrations occur.
Date: September 1943
Creator: Feingold, Arnold M.
Partner: UNT Libraries Government Documents Department

Wind-Tunnel Investigation of a Low-Drag Airfoil Section with a Double Slotted Flap

Description: From Summary: "Tests were made of an 0.309-chord double-slotted flap on an NACA 65, 3-118, a equals 1.0 airfoil section to determine drag, lift, and pitching-moment characteristics for a range of flap deflections. Results indicate that combination of a low-drag airfoil and a double-slotted flap, of which the two parts moved as a single unit, gave higher maximum lift coefficients than have been obtained with plain, split, or slotted flaps on low-drag airfoils. Pitching moments were comparable to those obtained with other high-lift devices on conventional airfoils for similar lift coefficients."
Date: September 1943
Creator: Bogdonoff, Seymour M.
Partner: UNT Libraries Government Documents Department